# Copyright (c) 2020, Frappe Technologies Pvt. Ltd. and contributors
# For license information, please see license.txt


import frappe
from frappe import _
from frappe.model.document import Document
from frappe.utils import get_link_to_form, getdate

from erpnext.accounts.utils import get_fiscal_year


class LowerDeductionCertificate(Document):
	def validate(self):
		self.validate_dates()
		self.validate_supplier_against_tax_category()

	def validate_dates(self):
		if getdate(self.valid_upto) < getdate(self.valid_from):
			frappe.throw(_("Valid Upto date cannot be before Valid From date"))

		fiscal_year = get_fiscal_year(fiscal_year=self.fiscal_year, as_dict=True)

		if not (fiscal_year.year_start_date <= getdate(self.valid_from) \
			<= fiscal_year.year_end_date):
			frappe.throw(_("Valid From date not in Fiscal Year {0}").format(frappe.bold(self.fiscal_year)))

		if not (fiscal_year.year_start_date <= getdate(self.valid_upto) \
			<= fiscal_year.year_end_date):
			frappe.throw(_("Valid Upto date not in Fiscal Year {0}").format(frappe.bold(self.fiscal_year)))

	def validate_supplier_against_tax_category(self):
		duplicate_certificate = frappe.db.get_value('Lower Deduction Certificate',
			{'supplier': self.supplier, 'tax_withholding_category': self.tax_withholding_category, 'name': ("!=", self.name)},
			['name', 'valid_from', 'valid_upto'], as_dict=True)
		if duplicate_certificate and self.are_dates_overlapping(duplicate_certificate):
			certificate_link = get_link_to_form('Lower Deduction Certificate', duplicate_certificate.name)
			frappe.throw(_("There is already a valid Lower Deduction Certificate {0} for Supplier {1} against category {2} for this time period.")
				.format(certificate_link, frappe.bold(self.supplier), frappe.bold(self.tax_withholding_category)))

	def are_dates_overlapping(self,duplicate_certificate):
		valid_from = duplicate_certificate.valid_from
		valid_upto = duplicate_certificate.valid_upto
		if valid_from <= getdate(self.valid_from) <= valid_upto:
			return True
		elif valid_from <= getdate(self.valid_upto) <= valid_upto:
			return True
		elif getdate(self.valid_from) <= valid_from and valid_upto <= getdate(self.valid_upto):
			return True
		return False
